Rotary jar



F. J. SPANG Oct. 30, 1934.

ROTARY JAR Filed oct.

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Patented ct. 30, 1.934

Unire STATES PATENT OFFICE l2 Claims.

This invention relates to a jar for drilling voporatie-ns for `looseningand removing a bit or other parts of the drill string Vfrom a well, andmore particularly to improvements in a jar suitable for L5 use `in therotary method of drilling.

In the rotary method of drilling, the drilling is accomplished byconstantly rotating a bit through forcegenerated at the surfaceand-transmitted yto the drill bit at the bottom of the well through aseries of tubular drill pipe sections.

During the drilling operation mud laden water is pumped through thedrill pipe to the bit and carries the'cuttingsiof the formation beingdrilled to the surface through the space between the drill pipe, and thebore of the well.

It is Anot an uncommon occurrence during the process of drilling for thebit and lower sections of the drill `pipe to become fast or stuck in thewell due toicrevices and other irregularities devel- Oping in the boreholes and from esoapement or loss of the mud laden water through porousformations. When such occurs it is frequently impossible to withdraw thetubing and bit from the well cya Straight upward pull, however, they maybe quickly released Aby jarring thereby avoiding the necessity ofdestroying them in order to effeet their removal.

Tosecure this jarring action, it is customary to interpose what iscommonly known as a jar at a suitable point in the string of tubulardrill pipe Ausually in the lower sections thereof relatively close tothebit. The jars now generally used are formed of two elements, one ofwhich is capable vof limited longitudinal movement relative `to theother to produce the jarring actions. Such jars have not provenaltogether satisfactory because it is impossible to raise the movableelement fast enough to create an impact of suilicient force to loosenthe bit'or other `tool stuck in the well and .also because the elementsof the jar become packedor clogged with sand cuttings and other dbrisoccasioned by the drilling operations and, as a result the jarringelements become tightly locked together, making the jar inopera- Itive.

It is an Aobject of this invention to provide a simple rugged jar,suitable `for use with rotary drilling tools, having telescoping jarringelements releasably locked together in their fully telescoped position,,the elements being automatically released forlimited relativemovementwhen subjected to a predetermined stress sunicient to causea stretching.in the drill pipe, Lwhereby a definite amount of `energy may bestoredup inthei tubular drill pipe' prior to the release of the elementswhich causes it to return rapidly toward normal condition when theelements are released; and providing for the denite arrestment of therelative movement of the jarring elements thus transmitting to the stuckbit or drill pipe a considerable portion of the developed inertia in theform of a jar.

Another object is to provide a jar suitable for use with rotary drillingtools having exceptionally ruggedjarring elements and means for keepingthe striking faces thereof free of sediment and dbris and means forexpelling the fluid and dbris from between the striking faces when ablow is struck.

Another object is to provide a jar suitable for use with rotary drillingtools having means for transmitting the rotative force through theplunger direct to the lower sections of the drill pipe, thus permittingfull use of the plunger head for a striking face and for a guide againstangular deflection.

A further object is to provide a jar suitable for use with rotarydrilling tools having rugged, simple means for releasably locking thejarring elements together, which means are automatically operative,releasable upon an upward pull of a denite determined force, andlockable upon slight compression force so that successive jarring blowsmay be struck.

A still further object is to provide a jar suitable for use with rotarydrilling tools having a releasable locking element for locking thejarring elements together, which locking means cannot be renderedinoperative by the packing of sand and dbris in and around it.

A still further object is to provide a `jar suitable for use with rotarydrilling tools having a simplemeans for releasably locking the elementstogether which means are located within the flow-course of thecirculating fluid so that it will be constantly washed free of sand anddbris and that the movement of the releasable locking means will beunrestricted by other parts of the jar or by sand or dbris.

A still further object is to provide a jar suitable -for use with rotarydrilling tools having a simple automatically `releasable locking meansrugged of construction, easily assembled, positive in operation, andoperative either while the elements are being rotated or in anon-rotating position.

These and other objects which will be hereinafter made readily apparentto those skilled in this particular art are accomplished by means ofthis invention, one embodiment of which is described in the followingspecification and illustrated in the accompanying drawing, wherein:

Figure 1 is a vertical section of my improved jar showing the jarringelements releasably locked in drilling position;

Fig. 2 is a vertical section of the jar showing the position of thejarring elements when the mandrel has been pulled upwardly to produce ajarring impact;

Fig. 3 is an enlarged View partially in elevation and partially insection of the member for releasably holding the jarring elements indrilling position;

Fig. 4 is an enlarged elevation of the lower end of the mandrel;

Fig. 5 is an enlarged vertical section of the lower connecting sub; and

Fig. 6 is a section taken on line VI-VI of Figure 1.

In general, a rotary jar made in accordance with my invention comprisestwo cylindrical jarring elements, ,oney 0f which is telescopicallymounted in the other and is capable of limited longitudinal movementrelative thereto so that when the jar is interposed in the drill string,the drill pipe may be moved upwardly to bring the two elements intostriking relation and produce a jarring action on the bit or other toolfastin the well. To increase the impact of the jarring elements, Iprovide a member for normally locking the two elements in their fullytelescoped or contracted position, which is adapted to automaticallyrelease when a predetermined stress, sufficient to cause a stretching inthe drill pipe, has been applied thereto, so that the energy developedby the stretching of the drill pipe will be utilized to bring the twoelements together with sufficient force to impart an exceedingly heavyjarring blow on the bit or other tool. This locking member may be sodesigned that any predetermined or desired amount of stretching willtake place in the drill pipe before the jarring elements will bereleased to produce the jarring impact.

To avoid any possibility of the member locking the jarring elementstogether becoming packed or clogged with sand and other cutting dbrisand thereby making the jar inoperative, the locking member is sodisposed in the jar that it is constantly washed with the mud ladenwater being pumped through the drill pipe to the bit; which effectivelyprevents the drill cuttings from wedging around the locking member. Toprovide for denite freedom of action, the path of travel of the lockingmember as it releases, is away from the working parts of the jar.

Referring tothe drawing in detail, 10 indicates a jar made in accordancewith my invention which is adapted to be interposed in a rotary drillingstring between the bit andthe tubular drill pipe. The jar 10 comprisesan outer cylindrical shell 1l having a tubular connecting sub 12threaded to the lower end thereof for connecting it to a drill bit orother tool (not shown). Slidably mounted for limitedilongitudinalmovement within the shell 11 is a cylindrical mandrel 13 the upperend ofwhich is connected to a tubular sub 14 for joining it to the lower kendof the drill pipe (not shown) through which rotary rmotion istransmitted to the drill bit. In order that the rotative force generatedon the surface will be transmitted through the jar, the lower end of themandrel has a series of splines 15 on the outer surface thereof whichengage with splines 16 on the inner surface of a portion 12a of the subl2, thus making a direct drive from the drill pipe to the bit or toolsecured to the sub. These splines 15 and 16 are so designed that theyare always in engagement regardless of the longitudinal position of themandrel in the shell 11 whereby any rotation of the mandrel will alwaysbe transmitted to the bit or other tool. The mandrel 13 is provided witha longitudinally extending passageway 17 through which the mud ladenwater pumped through the drill pipe is conveyed to the drill bit.

The longitudinal sliding movement of the mandrel 13 within the shell 1lis limited in one direction by the end of the mandrel striking against ithe portion 12a of the sub 12 and in the opposite direction by ashoulder 18 on the outer surface of the mandrel which engages a shoulder19 on the inner surface of the shell. This shoulder 18 forms a hammerwhich is adapted to strike vagainst the shoulder or anvil 19, when anupward pull is placed on the drill pipe, to produce a jarring impact forloosening the tool fastened to the connecting sub 12.

l In orderto increase the impact with which the hammer 18 strikes theanvil 19, I provide means for locking the mandrel against longitudinalmovement relative to the shell, which are adapted to automaticallyrelease the mandrel when an upward pull of sufficient force to cause astretching in the drill pipe has been applied thereto whereby the energyreleased by the contracting of the drill pipe will be utilized tosuddenly move the hammer against the anvil and impart an exceedinglyheavy blow to the tools fast in the well. This locking means which isdisposed in the passageway 17, of the mandrel 13 and connected to theportion 12a of the sub 12, comprises a cylindrical member 2O having aseries of longitudinally extending slots 21 intermediate of its lengthforming a series of leaf springs 22 connected together at each end bycollars 23. Each of these leaf springs 22 has a beveled latch 24 formedthereon which is adapted to seat over a sloping face 25 of a groove 26formed on the inner surface of the mandrel 13 and normally hold theelements of the jar in drilling position (Fig. 1).

From this construction it is apparent when the bit or lower end of thedrill string become stuck or fast in the bore hole, the jar 10 isactuated to loosen the stuck tools by a straight upward pull on thedrill pipe. This upward movement ofthe drill pipe is transmitted to themandrel 13 and causes the latches 24 to slide on the surface 25 and bendthe leaf springs 22 inwardly. When the upward pull applied to the drillpipe reaches a predetermined stress, the latches are designed to releasethe mandrel and permit it to move rapidly upward so that the hammer 1S"lllilI 25 on the mandrel and the jar is then in position to be againactuated to impart another jarring blow to the drill or other tool.

So that a stretching action will take place in the drill'pipe, thecylindrical member 20 is so designed and is of such material and sizethat applied to the drill pipe.

away from the hammer 18.

the latches 24 remain seated against the surface 25 until apredetermined upward force has been By making the locking 'member in theform of a cylindrical series of leafwsprings supported at both ends, theangle between the beveled latches and the sloping surface on the mandrelremains substantially the same regardless of the degree of compressionof the springs. As a result a constantly increasing force is necessaryto fully compress the springs to permit the latches 24 to disengage orslide off the surface 25. Thus, it is apparent that with my improvedspring member a predetermined amount of stretching will occur in thedrill pipe before the spring releases the mandrel.

So that the springs 22 will not become packed or clogged with sand andother cutting dbris, the cylindrical member 20 is so disposed within thepassageway 17 of the mandrel that the leaf springs 22 will becontinually washed by the mud laden water pumped through the drill pipe.By so locating the cylindrical member 20, the springs 22 are caused tomove inwardly into the passageway 17 to release the mandrel and, as aresult,

the movement of these leaf springs will not be restricted by the otherparts of the jar, or by sand and other dbris and it is impossible forthe jar to become clogged and inoperative.

To insure a clean striking surface on the ham-- mer 18 so that a solidblow will be struck against the anvil i9, passageways 2'l'and 28 areformed in the mandrel 13 whichlead from the shoulder 18 to thepassageway 17 and permit the sand and other dbris which has worked intothe jar between the shell and the mandrel, to be washed The water forwashing the hammer isforoed through openings 29 drilled at an anglethrough the wall of the mandrel above a reduced bore portion 17a of thepassageway 17. I'ihis reduced bore 17a tends to retard the ow of waterthrough the passageway 17 and forces a portion thereof through theopenings 29 which deliver it tc the shoulder 18 and from which it iscarried back into the passageway .i7 'through the passageways 27 and 28.

To prevent leakage of the mud laden water and to keep sand and otherdebris from collecting between the shell and the mandrel, the interiorof the V'upper end of the shell is made larger in .diameter than thecentral portion thereof to rev'ceive' a packing 30 and a packing gland30a which sumcient to stretch the drill pipe to a predetermined stresspoint, may be applied to the drill pipe before the elements of the jarwill release. When the cylindrical leaf springs have been comy pressedsuiciently to suddenly release the jarring clogged and consequently, isalways capable Vof beingoperated.

While I have described one embodiment of my invention, it is to beunderstood that certain changes, modifications, substitutions andomissions may be made therein without departing either from the spiritof my invention `or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. A rotary jar comprising an outer shell having an anvil formed on theinner surface thereof, a cylindrical mandrel slidably mounted in saidshell and having a longitudinallylextending passageway therein, a hammeron said mandrel, means permitting limited longitudinal movement betweenthe shell and the mandrel, and `means normally holding said mandrel andshell against relative longitudinal movement and releasing'underpredetermined pull to permit the hammer to strike said anvil and set upa jarring action, said last-mentioned means including a cylindricalmember associated with said shell and extending` into the tubularmandrel, said cylindrical member having a series of longitudinallyextending slots therein forming a series of leaf springs terminating ateach end in an integrallcollar, and a beveled latch member on each ofsaid leaf springs adapted to seat overa sloping face on the innersurface of said mandrel, the latch member on each of said leaf springsbeing so arranged that substantially the same angle is maintainedbetween the beveled surfaces `and the sloping face on the mandrel whenthe leaf springs are depressed whereby a constantly increasing pull isnecessary to release the mandrel.

2. A rotary jar comprising an outer shell, a tubular sub connected tothe end of said shell, a mandrel slidably mounted in said shell, andhaving a longitudinally extending passageway therein, interengagingmeans on said sub and mandrel for preventing rotation of said mandrelrelative to said sub, means secured to said sub and extending into thepassageway in said mandrel for releasably holding said Imandrel againstlongitudinal movement relative to said shell, and means for arrestingthe movement of said mandrel when said holding means have been releasedto impart a jarring blow to said shell.

3. The invention as claimed in claim 2, in which a cylindrical series ofleaf springs is connected to the sub and extends into the passageway inthe mandrel for releasably holding the mandrel against longitudinalmovement relative to the shell.

4. The invention as claimed in claim 2, in which a cylindrical memberhaving a plurality of longitudinally extending slots is connected to thesub and extends into the passageway in said mandrel and each portin ofthe cylindrical member between the slots is provided with a latch forreleasably holding the mandrel against longitudinal movement relative tothe shell.

5. The invention as claimed in claim 2, in which a longitudinallyslotted member having a series of latches on its outer surface adaptedto seat in a groove formed on the mandrel, is utilized for releasablyholding the mandred against longitudinal movement relative to the shell.

6. A rotary jar comprising an outer shell having a shoulder on the innersurface thereof, a mandrel telescopically mounted for limitedlongitudinal movement in said shell and having a shoulder thereon forengaging the shoulder on lsaid shell to arrest the movement thereof,said mandrel having a longitudinally extending water passageway thereinand a series of openings formed in the wall thereof, at differentelevations along its length, connecting said passageway with the outersurface thereof, means for forcing water to pass to the exterior of saidmandrel through theupper of said openings and back into said passagewaythrough the lower of said openings, whereby the shoulder on said mandrelwill be kept free of sand and other dbris.

7. A rotary jar comprising an outer shell, a mandrel telescopicallymounted for limited longitudinal movement in said shell and having alongitudinally extending water passageway therein, a shoulder on saidmandrel, said mandrel having a series of openings therein above saidshoulder connecting said passageway with the outer surface of themandrel, and a series of openings leading from the face of said shoulderinto said passageway, and a reduced bore portion in said passagewaybetween said upper and lower series of openings whereby a portion of thewater in said passageway is forced through the upper series of openingsonto said shoulder and returned to said passageway through the lower ofsaid openings.

8. A rotary jar comprising an outer shell, a mandrel telescopicallymounted for limited longitudinal movement in said shell and having alongitudinally extending water passageway therein, and means forarresting the longitudinal movement of said mandrelrelative to saidshell, said mandrel having an upper and lower series of openings in thewall thereof for diverting a portion of said water from said passagewayto cleanse said arresting means.

9. A rotary jar comprising an outer shell, a

"mandrel slidably mounted on said shell and having a longitudinallyextending water passage therein, means for releasably locking saidmandrel against movement in said shell, means for arresting the movementVof said mandrel when it has been released, means for cleansinggitudinal movement relative thereto from a normal contracted position toan expanded position, coacting surfaces on said mandrel and shellinterengageable to arrest movement of said mandrel when in expandedposition, said mandrel having a longitudinally extending waterpassageway therein and a series of openings formed in the wall thereof,a latching member for locking said mandrel in its contracted position,adapted to release on application of a predetermined force, saidlatching member being disposed in the water passageway in the mandrelwhereby dbris is continually washed therefrom, and means for circulatingwashing water through the openings in said mandrel to cleanse saidcoacting surfaces.

11, A rotary jar comprising a shell, a mandrel telescopicall'yl mountedfor longitudinal movement within said shell, said mandrel having alongitudinally extending Water passageway therethrough and a series ofopenings in the Wall thereof connecting the inner and outer surfacesthereof, means for arresting the longitudinal movement of said mandrel,and a cylindrical latching member adapted to loclr` said mandrel in itscontracted position and release the mandrel on application of apredetermined force thereto, said latching member being disposed in saidpassageway whereby dbris is continually washed therefrom, aportion ofsaid passageway in said mandrel being of reduced bore to build up a backpressure in said passageway and cause water to flow through the openingsin said mandrel and cleanse the arresting means.

12. A rotary jar comprising a sheil having a shoulder on the innersurface thereof, a mandrel telescopically mounted for limitedlongitudinal movement within said shell and having a shoulder thereonfor engaging the shoulder on said shell to arrest the movement thereof,said mandrel having a longitudinally extending water passageway therein,and a series of openings in the Wall thereof on each side of saidshoulder, a reduced bore portion in said passageway between the seriesof openings and a cylindrical spring latching member adapted to releaseupon application of a predetermined force thereto, for normally lockingsaid mandrel in its contracted position within said shell, said latchingmember being disposed in said Water passageway whereby it is continuallysubjected to a washing liquid.

FERDINAND J. SPANG.

